While the recent image forming apparatus is capable of providing a wide variety of image processing functions with high capability, the time required for staring up the image forming apparatus such as to execute all the application programs capable of providing the image processing functions tends to be longer, thus requiring the user to wait for the longer time until the user can use the image forming apparatus.
In order to reduce the time for staring up the image forming apparatus, the Japanese Patent Application Publication No. 2005-189507 discloses an image forming apparatus, which includes a sub CPU, an engine CPU, and a system CPU. The execution of the sub CPU is completed before the execution of the engine CPU and the system CPU. The sub CPU controls the image fixing operation of the fixing device to reduce the time required for the image forming apparatus to be in the state in which the image fixing operation is available after the time when the power is turned on.
However, the image forming apparatus disclosed in the Japanese Patent Application Publication No. 2005-189507 can perform the image forming operation only after the execution of the system CPU has completed. While the fixing device is caused to be in the state where the image fixing operation is available at the reduced time, the image forming operation is not performed unless the execution of the system CPU has completed. When the time required for the system CPU to execute increases, the time required for the image forming apparatus to be ready for image forming operation may also increase.
Further, the user at the image forming apparatus may not need to use the image forming function, but may only desire to use only a part of the image processing functions provided by the image forming apparatus. Even when the user only desires to use the part of the image processing functions that requires no image forming, such image processing function cannot be made available for use by the user until the execution of the system CPU has completed.